JPS5862400A - Motor fan - Google Patents

Abstract

PURPOSE:To make the passage area of a return guide vane inlet smaller than the passage area of a diffuser blade outlet and as well to form a smooth accelerating passage for enhacing fluid dynamic performance, by forming, in specific shapes, the outer peripheries of diffusers, partition plates and return guide vanes. CONSTITUTION:A partition plate 7 has a diameter of curvature substantially equal to or larger than the axial width b2 of the outlet of a diffuser blade 9, that is, 1-1.2 times larger than the latter, at the periphery of the partition plate 7 in a meridionally cross-sectioned shape, and the passage width b5 of the inlet of a return guide vane 10 is made smaller than the axial width b2 of the outlet of the diffuser blade 9 so that the flow velocity at the inlet of the return guide vane 10 is higher than that at the outlet of the diffuser blade 9. With this arrangement, a fluid passage from the outlet of the diffuser blade 9 to the inlet of the return guide vane 10 constitutes a smooth accelerating passage, and has a sufficiently large inner curvature so that flow separation, pressure loss or the like may be eliminated, causing fluid dynamic performance to be remarkably enhanced, and further, enabling noise reduction to be brought about.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a household acid'Am remover 0 electric blower, and in particular, to improve its physical performance and reduce noise, a conventionally used 1JtNh blower will be explained with reference to FIGS. 1 to 4. do. FIG. 1 is a longitudinal sectional view of an electric blower, in which reference numeral 1 represents an electric motor, and a centrifugal impeller 3 is fastened to one end of a rotating shaft 2 by a nut 4. Outside KVi of impeller 3,
A casing 5 having a conical front surface and a cylindrical side surface is disposed, and is fitted into a disc-shaped end bracket 6 provided at the end of the electric motor 1 on the blower side to form a space inside.

The impeller is housed therein. A disk-shaped partition plate 7 is arranged inside the casing 5 at the rear surface (anti-suction side) of the impeller 3 and is fixed to the end bracket 6 and the electric motor 1 with bolts 8 at multiple locations in the circumferential direction. . Partition plate 7
On the front surface (suction side) of the impeller 3 and on the outer periphery of the impeller 3, diffuser blades 9 in the form of a single circular blade row are protruded, and on the rear surface of the partition plate 7, return guide vanes 10 are protruded to form a fluid passage. . Further, an annular gap 11 is formed between the outer peripheral end of the partition plate 7 and the inner peripheral surface of the casing 5. As the impeller 3 rotates, air is sucked in through the suction port 12 and pressurized by one impeller, and then decelerated through the fluid passage consisting of the stiff user blade 9, the circular gap 11, and the return guide blade 10 through ηL. At the same time, the dynamic pressure is converted to static pressure, which flows into the inside of the electric motor through the suction 13 provided at the end bracket 6 and the end of the electric motor area, and after cooling the electric motor, the other end of the electric motor or It flows out through openings (not shown) provided on the sides. 2, 3, and 4 are axial views of the diffuser vane, return guide vane, and intake port, respectively.

The configuration of the diffuser blades, return guide vanes, etc. used in the electric blower with the above configuration is similar to that of the conventional large-sized blowers used in the Shiro and Sho phase areas. There are particular restrictions on size, shape, etc. In other words, the ratio of the diffuser outlet diameter to the inlet diameter is 1.4 for large-sized Shins.
It is normal for the quality to be as large as ~2, but - for dynamic blowers.

It can only take a small value of 1.15 to 1.25, and the axial dimension is extremely limited by its colleagues.

Therefore, there is no room for sufficient bending in the flow path from the diffuser blade to the return guide blade.

However, conventional electric blowers have not been designed to construct efficient fluid passages within such a restricted space, and therefore have drawbacks such as low fluid performance and high noise levels.

If we look at the above point with the example in Figure 1, we can see that the partition plate is only slightly rounded at the outer peripheral edge in its calf plane cross section (the meridian plane is the plane that includes the center line of the rotational axis), It forms a sharp bend.

The return guide vanes also have a large axial width at the inlet;
Although the axial width is gradually determined toward the center, the passage area of the return guide blade inlet is larger than the passage area of the diffuser blade outlet, which is advantageous when considered in conjunction with the sharp bend mentioned above. It is not a passageway shape. When the inventor measured the flow at the inlet of the return guide vane using a small probe, flow separation occurred over a considerable portion of the width of one passage.

It was confirmed that this was the cause of performance deterioration.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide an electric blower for a household vacuum cleaner with high fluid performance and low noise level.

A feature of the present invention is that the partition plate has a curvature diameter as large as the axial width of the outlet (the curvature diameter is twice the curvature radius) at the outer peripheral end of the diffuser 171 in the meridional cross-sectional shape, and The width in the q11 direction of the inlet of the guide vane is smaller than the width in the axial direction of the outlet of the diffuser blade. This prevents the flow from separating in some areas and reduces performance. 1
An embodiment of this invention will be explained with reference to FIG. FIG. 1 shows only the outer peripheral portions of the diffuser blade, partition plate, and return guide blade, and the other parts are the same as those shown in FIGS. 1 to 4, so the description of FIG. 5 and the description thereof will be omitted. As shown in the figure, the partition plate 7 has a large curvature diameter at the outer circumferential portion in the meridian UkJ cross-sectional shape, which is equal to or more than (1 to 1.2 times) the axial width of the knife user blade outlet, and The passage width of the return guide vane population is made smaller than the previous day's pib so that the flow velocity at the return guide vane inlet is higher than the flow velocity at the diffuser vane outlet. More precisely, the passage area at the return guide vane inlet is determined to be smaller than the passage area at the diffuser vane outlet. Here, the passage area is defined by the following formula.

Diffuser blade outlet passage area AI YuπDlblsiaβ.

Return guide wing entrance #! I area A * = K DB b 1 sin β.

AFi passage area, D is the diameter with respect to the center of rotation, β is the angle that the blade or flow makes with respect to the circumferential direction, suffix 2 represents the diffuser blade outlet, and suffix 5 represents the return guide blade inlet.

In the above relationship, let Dt''Dll, and β,==β.

Then b! >bl is a requirement. (bs=10.6~
0.8) b, Generally, the requirement is A t > A *, and in order to allow the flow to flow into the return guide vane without collision, a slight β
,〉β,. ) Furthermore, as an additional requirement, the passage area A (defined below) of the annular gap 11 formed between the casing 5 and the outer peripheral end of the partition plate 7 is set to be smaller than the above A, and larger than the above A. A! >A, >A5).

Round mound-shaped gap passage area A m = (D4” DB”) sin β.

The subscript 4 represents the inner circumference of the casing cylinder, the subscript 3 represents the outer peripheral edge of the partition plate, and the subscript represents the average value for the annular gap.

Figure M6 and Figure 7 show other embodiments of this invention.
The outer peripheral part of the partition plate 7 communicates the diffuser side and the return flow path side at an angle with respect to the circumferential direction! A plurality of round slits 14 are provided. This slit forms a part of the acceleration path from the diffuser blade outlet to the return guide blade population, helps guide the flow, and prevents separation of the flow at the outer peripheral edge of the partition plate, thereby preventing noise generation. have a role. In other words, with a diffuser without blades, there is nothing to restrict the flow in the circumferential direction, so if a separation occurs in a part of the flow for some reason, this will propagate in the circumferential direction (swivel stall) and become unstable. However, this slit serves to prevent this phenomenon.

A passage area A that is the sum of the slit 14 and the annular gap 11,
(below) is set to be smaller than the diffuser blade outlet passage area A and larger than the return guide blade inlet passage surface Mas.

A, =-(Dt-'f)B'') sinβm+naca
is the width of the slit, C is the depth, n is the number of slits, and subscript 4 is the inner circumference of the Kenong cylinder.

The subscript 3 represents the outer peripheral edge of the partition plate, and the subscript represents the average value for the annular gap. Note that β, ζβ.

Therefore, it is appropriate to select β to be an intermediate value between β and β.

By forming the outer periphery of the diffuser, partition plate, and return guide vane as described above, the fluid passage from the diffuser blade outlet to the return guide vane inlet is formed into a smooth acceleration passage, and the inner radius of curvature is made sufficiently large. In addition, since the guiding effect of the slit can be added, the performance is significantly improved without causing flow separation, pressure loss, unstable performance, etc., and furthermore, the noise can be reduced. In addition, since the fluid passage is formed as described above, a special space is not required; it can be accommodated within the same space as the conventional one. Furthermore, by gradually increasing the axial width from the return guide vane inlet to the outlet, the deceleration passage leading to the outlet can be formed without any difficulty.

FIG. 6 shows the experimental results showing the two effects of the above implementation.

The figure shows the relationship between the power (static pressure) H of the electric blower and the power (static pressure) H of the electric blower. In addition, the broken line shows the characteristics when the shape of the partition plate/return guide vane part is the conventional type and the shape of the diffuser is the same, and the chain line shows the characteristics when the shape of the diffuser is different (designed with a large number of blades in the conventional method). shows the characteristics of From the figure, it can be seen that according to this embodiment, higher pressure can be generated in the medium to small wind cover than in the case of the conventional partition plate, and higher pressure can be obtained in the entire wind cover area than in the case of the conventional diffuser. In addition, when the slits are provided, the noise level is reduced by 3 to 4 dB over a wide range of wind noise.As can be seen from the above explanation, in this invention, the partition plate has a meridional cross-section shape, and the exit of the diffuser blade is located at the outer peripheral end. By virtue of the fact that the curvature diameter is as large as the axial width of the electric blower, and the axial width of the return guide blade inlet is smaller than the axial width of the diffuser blade outlet, the annular gap from the diffuser blade outlet of the electric blower is The fluid passage leading to the return guide vane inlet can be made into a smooth acceleration passage, which prevents flow separation, pressure loss, unstable operation, etc., and has a great effect on improving the performance of the blower. can be done.

In addition, multiple slits are provided on the outer periphery of the partition plate that connect the diffuser side and the return guide vane side and are inclined with respect to the circumferential direction, which improves the guiding effect in the acceleration path and reduces noise. .

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view showing a conventional electric transmission machine, Figure 2 is an axial view a (arrow view) of the diffuser in Figure 1, and Figure 3 is the axis of the return guide vane in Figure 1. Directional view (4H arrow view), 4th
The figure is a @11 direction view (■ arrow view) of the 1ta inlet in Fig. 1, Fig. 5 is an MIfr side view of the partition plate of this invention, and Fig. 6
The figure is an M sectional view of a partition plate of another embodiment of this invention.
Figure 7 is a view taken in the direction of arrow A in Figure 6, and Figure M8 is a blower characteristic diagram showing the effects of this invention. 3... Impeller, 7... Partition plate, 9... Diffuser blade, 10... Return guide blade, 11... Annular gap,
14...Slit. Agent Patent Attorney Toshiyuki Hakata No. 22 'fJ3 Mouth//) 4th Ward Figure 5) 5 6 Giant Figure 7

Claims (1)

[Claims] 1. A centrifugal impeller is coupled to a rotating shaft of an electric motor, a cylindrical casing is provided on the outside of the centrifugal impeller, and a disk-shaped partition plate is arranged on the back of the impeller. diffuser blades on the front of the impeller and around the outer circumference of the impeller. In addition, in the case where guide wings are protruded from the rear of the partition plate and a circular gap is formed between the outer peripheral edge of the partition plate and the casing, the shape of one meridian face of the partition plate is the outer peripheral edge. The diameter of curvature in the axial direction of the diffuser blade outlet is approximately equal to or larger than that of the diffuser blade outlet, and the axial width of the return guide blade inlet is smaller than the axial width of the diffuser blade outlet, and the flow velocity at the return guide blade inlet is equal to or greater than that of the diffuser blade outlet. An electric blower characterized by being designed to be faster than the flow velocity. 2. Particularly, in lt'F claim 1, the passage fi product πDl 1) l sin β at the outlet of the diffuser blade
2 (where D is the diameter with respect to the center of rotation, b is the axial direction II, and β is the angle that the blade or flow makes with the circumferential direction. The subscript 2 represents the diffuser blade outlet). The passage in the circular gap between the partition plate and the casing (the inner periphery of the cylindrical part of the sink, the subscript 3 represents the outer peripheral edge of the partition plate, the subscript represents the average for the circular gap) is small, and the passage in the circular gap is small. Passage area of return guide vane inlet πDlb than area
lsiaβS (where the subscript 5 represents the return guide vane inlet) is small. An electric blower characterized in that the entire fluid passage from the diffuser blade outlet to the return guide blade inlet serves as an acceleration passage. 1 A centrifugal impeller is connected to the rotating shaft of an electric motor, a cylindrical casing is provided on the outside of the centrifugal impeller, and a disk-shaped partition plate is placed on the back of the impeller, and the front surface of the partition plate and the outer periphery of the impeller are diffuser wings. In addition, in a device in which return guide vanes are provided protruding from the rear surface of the partition plate and an annular gap is formed between the outer peripheral end of the partition plate and the casing, the calf surface cross-sectional shape of the partition plate is the diffuser blade at the outer peripheral end. The diameter of curvature is equal to or larger than the axial width of the outlet, and the axial width of the return guide vane inlet is smaller than the axial width of the diffuser blade outlet, and the flow velocity at the return guide vane inlet is lower than the flow velocity at the diffuser vane outlet. 1. An electric blower, characterized in that a plurality of slits are provided in the outer circumferential portion of a partition plate to connect a diffuser side and a return guide blade side and are inclined with respect to the circumferential direction. 4. In claim 3, the area of the passage that also extends to the exit of the diffuser blade is A, and the area of the passage at the exit of the return guide blade is A5. When the total cross-sectional area of the slit is A, At>A. >A An electric blower characterized in that the fluid passage from the diffuser blade outlet to the return guide blade inlet is accelerated as a whole.